Riverside County Sheriff Chad Bianco, who is a leading Republican candidate for governor, has seized more than 650,000 ballots from last November’s election and is investigating whether they were fraudulently counted.

“This investigation is simple: Physically count the ballots and compare that result with the total votes recorded,” Bianco said at a news conference Friday.

The unusual probe drew a sharp rebuke from California Atty. Gen. Rob Bonta, who said in a statement Friday that it is “unprecedented in both scope and scale” and appears “not to be based on facts or evidence.”

“There is no indication, anywhere in the United States, of widespread voter fraud,” Bonta said. “Counts, recounts, hand counts, audits, and court cases all support this.”